Carburetors



March 26,1957 Z 1 2,786,658

CARBURE'IORS Filed May 16, 1955 JAIL/4" 74/ United States Patfif 2,786,658 CARBURETORS Pierre DurieaPtins, France Application May 16, -1955-,-SerialNo.508,745 Claims priority, application'France May 24, 1954 Claims. 01.261 41 iMy invention has for its object improvements in carburetors, chiefly in those which are devoid of a constant level vat. Qarburetors of this type as designed hitherto show the drawback of an insuflicient fluid tightness when the throttle valve is open while moreover it is impossible to obtain with such carburetors an automatic idling operation.

My invention has for its chief object on the one hand removal of these drawbacks and, on the other, the production of the desired automaticity in the throughput of gasoline under the action of the suctionof the engine. Fu-rther-n-iore my improved carburetor allows forming through operation of the accelerator a provision of fuel which provides subsequently for an easy starting of the engine when cold and also producing through the mere operation of said carburetor a modification in the proportion between air and fuel.

I According to my invention, 1 resort to a suitably shaped needle valve rigid with a coaxial valve submitted to the action of the depression produced by the suction of the engine fed with combustible mixture by the carburetor, said needle-valve serving as means for stopping the flow of fuel into the carburetor. I I

According to a further feature of my invention, a first seat is provided for said valve rigid with the needle valve inside a shell controlling the admission of air or "the like ccrnbustive gas and the output of combustible mixture; "the said shell is allowed to execute a free strokeof predetermined magnitude over a guiding member submitted to the action of the accelerator and a "second seat is provided on the said guiding member for the said flap valve rigid with the needle valve. I I

II My invention includes furthermore arrangements to be described hereinafter together with those already referred l0..

My invention covers a number of embodiments of my int-proved carburetor and of the different components of the I latter. I

I The single figure of accompanying drawing shows diagrammatically andon a scale larger than unity one of the said embodiments. I will now disclose with referenceto said drawing the embodiment illustrated therein by way of example and by no means in a limiting 'Sense.

As illustrated; the carburetor includes, in addition to its body 1, a needle valve 2 the conical tip 3 of which is adapted to engage the edge of, the opening4 formed in a boss 5 acting as a jet and rigid withthe body 1'. The upper end of the needle valve carries a nap valve 6 preferably made of an elastic material which cannot be attacked by the fuel. This valve 6 cooperates with a first seat 7 formed inside the floating shell 8 dird'with' a second seat 9 formed on a member 10 acting a u'ide for the floating shell 8, said member It) beih'gco'nnected 2 with a Bowden cable 19 leading to a control handle which is not illustrated. I I I I I I I A first spring 11 is fitted between awasher 1'2 lying over the upper section of reduced diameter of the guiding member ltl and the cover of the body 1. I I I II:

A second spring 13 is fitted between said washer 1 2 and the floating shell 8, I

The shell 8 is -provided with a groove 81: cut along one of the generating lines of its outer surface, said groove extending preferably in a plane passing through theaitis of the pipe 20 leading the combustible mixture from the carburetor to the engine.

A sort of elastic key 14- made of piano wire or the like is shaped as illustrated in the drawing and is secured through its upper end in a blind hole formed in the shell '8 while the body of the said keyld is resiliently fitted inside a groove in formed longitudinally in the body of the carburetor; the lower end of the key 14 is bent iri= wardly to engage the lower end of the shell 8 and to pro} ject into the bore formed by the latter; the key 14 and the groove in are shown in dot and dash lines because in actual practice they lie in an axial plane which does not pass through the input nozzle 21 feeding air into the carburetor. It may use instead of such a key a coil spring engaging the train body and braking the movements er the shell. I I

An annular vat 15 formed inside the lower end of the body 1 surrounds the boss 5. Said boss constitutes jas' a matter of fact and as described herein'above' the jet "of the carburetor. The opening 4 in said boss extends the shape of a narrow bore 4:: and of a still narrower bore 412 forming the gauged opening of the carburetor jet. The lower end of said boss projecting outwardly of the body 1 forms a tapped connection adapted to engage the pipe 22 feeding the fuel into the carburetor. I

The needle valve 2 extends downwardly through a comparatively long distance beyond its conical tip 3 to form a conical stem 2a engaging the jet. A throttled section 16 in the ipe 22 limits the admission of fuel to an amount defined by its gauge designed in a'cc'ordaiice with the type of engine to be fed. I

The guiding member 10 is provided with transverse openings as shown at 10a connecting the inside of said member with the suction of the engine through the groove 8a in the shell 8. I

A channel 17 extends through the wall of the body it so as to connect the bottom of the vat 15 in the latter with the output pipe 20 of the carburetor and to allow the gasoline contained in said vat 15 to be sucked out at the starting of the engine.

To provide for a modification in the proportions of the ai r and gasoline mixture during the running in period and also and chiefly during. more or less cold weather, I may modify the location of the flap valve 6 for instance by laying over itone or more washers which allow a m'od'ificatiohin its thickness whereby the amplitude stroke of said valve 6 and of the needle valve 2 is modilied.

The operation or" the carburetor is as follows: the; s'uction'p'roduced by the engine is transmitted through the groove do out in the periphery of the shell 8 so as to create a vacuum above the latter which rises tea co'rrepondi'ng 'ext'eht. Said vacuum acts also on tli valve 6 through-the openingslila mare guiding jm'e ber 10. The needle valve 2 is thus urged unwaidl releases the opening of the je t' d. I lfh'e valve s thus always the movements of the shell 8 while the motor engine is operative so that the needle valve 2 uncovers to a varying extent the opening 4 of the jet. engine stops, the shell 8 drops back and carries along with it the needle valve 2 which closes again the jet opening 4.

The automaticity of the gasoline throughput is obtained by giving the needle valve 2 a predetermined weight. When the carburetor is open under full load conditions, while the engine revolves at a slow rate, the engine requires a lesser amount of fuel and of air; the suction being-smaller, the system'including the needle valve 2 and the flap valve 6 operates after the manner of a piston inside a cylinder and forms a sort of airborne float which adjusts automatically the throughput of gasoline.

The starting under low temperature conditions is ob- .tained readily and reliably by drawing out the cable 19 The elastic key ld-carried by the shell 3 is thus also raised and its lower end projectingbeyond the edge of said shell inwardly engages the valve 6 so that when the latter has risen it allows fuel to be sucked out of the jet and to drop back to fill the vat 15 by an amount .suflicient for the starting of the engine.

The shell 8 is adapted to slide over the guiding member 10. The whole arrangement rises since the different parts are submitted simultaneously to suction and the valve 6 abuts against the seat 7 formed on the shell 8 and is held in contact with said seat by the suction exerted by the engine.

When the engine stops, the needle valve 2 drops under the action of gravity and its conical tip 3 rests on the o edge of the opening of the pilot jet and this contacting When the 1 the admission of fuel in accordance with one of the de sired objects of my invention.

Obviously, the needle valve 2 should be of a reduced weight so that it may be raised easily by the comparatively small depression produced by the engine running at fullload.

When the cable 19 is released, the weight of the shell 8 isassociated with the weight of the needle valve 2 so that any risk of a leak of fuel is cut out, in spite of the light weight of the needle valve 2, which provides for a further object of my invention. This fluid tightness and also the automatic idling are obtained as a consequence of the independent behaviour of the shell 8 and of its .intothe inside of the guiding member 10, but it cannot lift the needle valves 2; however the independence of the shell 8 with reference to the uiding member 10 allows said shell to follow the action of the suction and to rise whereby the valve 6 is allowed to rise in its turn and engages the seat 7 on the shell so as to allow an amount of fuel to pass which is sufiicient for idling purposes. The location-of the needle valve 2 with reference to the shell 8 is then unvarying.

In order to modify at any desired point of its acceleration stroke the proportions of air and fuel in the mixture, it is sufficieut to release slightly the accelerator pedal.

By reason of the above referred to independence of the shell 3 with reference to the guiding member 10, the

over the pilot jet and reduces consequently the throughput of fuel while the shell 8 is still held frictionally in positionby the yielding key 1 and allowsthe same amount of air to enter, the ratio between the amounts of air and of fuel being consequently modified.

The spring 13 limiting the possible shifting between th guiding member 19 and the shell 8 provides as it expands during the latter part of the downward movement of the shell 8 for a cutting out of said shifting and a closing of the admission of gasoline.

My invention is obviously not limited to the above described embodiment and it covers all the modifications thereof falling within the scope of accompanying claims.

What I claim is:

l. In a carburetor for an internal combustion engine, the combination of a casing provided with a lateral air input pipe, with a lateral mixture output pipe adapted to be connected with the suction pipe of the engine and with a fuelnozzle opening vertically upwards into the lower end of the casing, a double valve including a needle valve vertically located above the opening of the nozzle inside the casing for cooperation therewith and a flap valve coaxially rigid with the upper end of the needle valve, a shell floatingly mounted inside the casing, having an upwardly facing centrally open cover, seating the flap valve coaxially and opening downwardly towards the bottom of the casing, the outer surface of said shell being provided with a longitudinal groove facing the output pipeconnected-with the suction pipe of the engine to connect permanently said output pipe with the part of the casing extending above the shell, said shell being adapted to be shifted vertically above a lowermost position closing the air input, means for preventing rotation of the shell with reference to the casing, a downwardly opening socket shaped guiding member slidingly mounted inside the opening in the shell cover and including a larger diameter lower section forming a seat for the shell cover, differential elastic means urging the shell and the guiding member in succession downwardly with reference to the casing, a hand operable cable through which the guiding member is adapted to be shifted upwardly and to draw along with it the shell against the action of said elastic means, the lower surfaces of the guiding member and of the bottom of the shell being provided each with an annular seat for cooperation with corresponding surfaces of the flap valve, means whereby the upper surface of the flap valve facing the inside of the guiding member is submitted to the pressure prevailing outside the latter when the shell is seated on the lower section of the guiding member, the upward movement of the shell under the action of suction through the engine over the guiding member against the action of the elastic means releasing the engagement of the seat on said shell and the corresponding surface on the fiap valve.

2. Ina carburetor for an internal combustion engine, the combination of a casing provided with a lateral air input pipe, with a lateral mixture output pipe adapted to be connected with the suction pipe of the engine and with a fuel nozzle opening vertically upwards into the lower end of the casing, the inner surface of the casing being provided with a vertical groove, a double valve including 7 a needle valve vertically located above the opening of the nozzle inside the casing for cooperation therewith and a flap valve coaxially rigid with the upper end of the needle valve, a shell floatingly mounted inside the casing, having an upwardly facing centrally open cover, seating the flap valve coaxially and opening downwardly towards the bottom of the casing, the outer surface of said shell being provided with a longitudinal groove facing the output pipe connected with the'suction pipe of the engine to connect permanently said output pipe with the part of the casing extending above the shell, said .shell being adapted to be shifted vertically above a lowermost position closing the air input, yielding means engaging the upper endof the shell, slidingly engaging with friction the vertical groove in the casing and including a member extending underneath the lower edge of theshell and adapted upon upward suction of the shell to engage the underside of the Hap valve and thereby raise the double valve to release the needle valve off the opening of'the nozzle, ,a downwardly opening socket shaped guiding member slidingly mounted inside the opening in the shell cover and including a larger diameter lower section forming a seat for the shell cover, differential elastic means urging the shell and the guiding member in succession downwardly with reference to the casing, a hand operable cable through which the guiding mem" her is adapted to be shifted upwardly and to draw along with it the shell against the action of the said elastic means, the lower surfaces of the guiding member and of the bottom of the shell being provided each with an annular seat for cooperation with corresponding surfaces of the flap valve, means whereby the upper surface of the flap valve facing the inside of the guiding member is submitted to the pressure prevailing outside the latter when the shell is seated on the lower section of the guiding member, the upward movement of the shell under the action of suction through the engine over the guiding member against the action of the elastic means releasing the engagement of the seat on said shell with the corre sponding surface on the flap valve.

3. In a carburetor for an internal combustion engine, the combination of a casing provided with a lateral air input pipe, with a lateral mixture output pipe adapted to be connected with the suction pipe of the engine and with a fuel nozzle opening vertically upwards into the lower end of the casing, said casing being provided with an annular recess in its bottom surrounding the fuel nozzle to form a fuel vat and furthermore with a channel connecting the lower end of said vat with the output pipe, a double valve including a needle valve vertically located above the opening of the nozzle inside the casing for cooperation therewith and a flap valve coaxially rigid with the upper end of the needle valve, a shell fioatingly mounted inside the casing, having an upwardly facing centrally open cover, seating the flap valve coaxially and opening downwardly towards the bottom of the casing, the outer surface of said shell being provided with a longitudinal groove facing the output pipe connected with the suction pipe of the engine to connect permanently said output pipe with the part of the casing extending above the shell, said shell being adapted to be shifted vertically above a lowermost position closing the air input, means for preventing rotation of the shell with ref erence to the casing, a downwardly opening socket shaped guiding member slidingly mounted inside the opening in the shell cover and including a larger diameter lower section forming a seat for the shell cover, differential elastic means urging the shell and the guiding member in succession downwardly with reference to the casing, a hand operable cable through which the guiding member is adapted to be shifted upwardly and to draw along with it the shell against the action of said elastic means, the lower surfaces of the guiding member and of the bottom of the shell being provided each with an'annular seat for cooperation with corresponding surfaces of the flap valve, means whereby the upper surface of the flap valve facing the inside of the guiding member is submitted to the pressure prevailing outside the latter when the shell is seated on the lower section of the guiding member, the upward movement of the shell under the action of suction through the engine over the guiding member against the action of the elastic means releasing the engagement of the seat on said shell with the corresponding surface on the flap valve.

4. In a carburetor for an internal combustion engine, the combination of a casing provided with a lateral air input pipe, with a lateral mixture output pipe adapted to be connected with the suction pipe of the engine and with a fuel nozzle opening vertically upwards into the lower end of the casing, the inner surface of the casing being provided with a vertical groove, said casing being provided with an annular recess in its bottom surrounding the fuel nozzle to form a fuel in and further with a ensure connecting "the lower end of said vat with the output pipe, a double valve including a needle valve vertically located above the opening of "the nozzle inside the casing for cooperation therewith and flap valve .coaxially'r'igid with the upper end of "the needle valve, a shell "floati'ng'ly mounted inside the casing, having "an upwardly facing centrally open cover, seating the flap valve eoaxially and opening downwardly towards the bottom of the casing, the outer surface of said shell being provided with alongitudinal groove facing the output pipe connected with the suction pipe of the engine to connect permanently said output pipe with the part of the casing extending above the shell, said shell being adapted to be shifted vertically above a lowermost position closing the air input, a downwardly opening laterally perforated socket shaped guiding member slidingly mounted inside the opening in the shell cover and including a large diameter lower section forming a seat for the shell cover, a key constituted by an elastic rod the main portion of which is frictionally engaged in the vertical groove of the casing, the upper end of which is fitted in the shell cover and the lower end of which is bent inwardly to engage the lower edge of the shell and to project inside the latter to an amount such that when the shell is raised by suction independently of the guiding member, said bent end raises the double valve arrangement to release the fuel nozzle, differential elastic means urging the shell and the guiding member in succession downwardly with reference to the casing, a hand operable cable through which the guiding member is adapted to be shifted upwardly and to draw along with it the shell against the action of said elastic means, the lower surface of the guiding member and of the bottom of the shell being provided each with an annular seat for cooperation with corresponding surfaces of the flap valve, the upward movement of the shell over the guiding member under the action of suction through the engine against the action of the elastic means releasing the engagement of the seat on said shell with the corresponding surface on the flap valve.

5. In a carburetor for an internal combustion engine, the combination of a casing provided with a lateral air input pipe, with a lateral mixture output pipe adapted to be connected with the suction pipe of the engine and with a fuel nozzle opening vertically upwards into the lower end of the casing, a double valve including a needle valve vertically located above the opening of the nozzle inside the casing for cooperation therewith and a flap valve coaxially rigid with the upper end of the needle valve, a shell floatingly mounted inside the casing, having an upwardly facing centrally open cover, seating the flap valve coaxially and opening downwardly towards the bottom of the casing, the outer surface of said shell being provided with a longitudinal groove facing the output pipe connected with the suction pipe of the engine to connect permanently said output pipe with the part of the casing extending above the shell, said shell being adapted to be shifted vertically above a lowermost position closing the air input, means for preventing rotation of the shell with reference to the casing, a downwardly opening socket shaped guiding member slidingly mounted inside the opening in the shell cover and including a larger diameter lower section forming a seat for the shell cover, a washer adapted to slide over the guiding member above a lowermost position engaging the latter at a distance above the shell cover, a spring fitted between the casing and said washer and urging the latter into its lowermost position, and thereby urging the guiding member downwards upon engagement of the washer with the latter, a further spring fitted between said washer and the upper surface of the shell cover to urge the latter downwardly when the washer has entered its lowermost position, a hand operable cable through which the guiding member is adapted to be shifted upwardly and to draw along with it the shell against the action of said springs, the lower surfaces of the guiding member and of the bottom of theshellbeing 'provided each with' an'annular 'seat' for cooperation with corresponding surfaces of the flap valve, to engage the latter simultaneously when the shell is in its normal operative engagement with the guiding member, the upward m ovem ent of the shell under the action of suction through the engine over the guiding member against the action of the springs releasing the engagement of the seat on said ,shell with the corresponding surface on the flap valve.

. References Cited in the file of this patent UNITED STATES PATENTS Skinner Sept. 8,

Smith et a1 June 30,

FOREIGN PATENTS Great Britain Jan. 2, 

